开菲尔粒中乳酸菌的筛选与发酵特性

以大肠杆菌ATCC25922和金黄色葡萄球菌ATCC25923为抑菌对象筛选开菲尔粒中具有抑菌功能的乳酸菌,将该乳酸菌株发酵上清液制成冻干粉,未纯化的抗菌肽质量浓度大于6.250?mg/mL时,对大肠杆菌ATCC25922和金黄色葡萄球菌ATCC25923抑菌效果显著,利用16S?rDNA方法,鉴定该菌株为干酪乳杆菌....

Screening and Fermentation Characteristics of Antimicrobial Lactic Acid Bacteria Isolated from Kefir Grains

Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 were used as test strains for screening ofantimicrobial lactic acid bacteria from kefir grains. The fermentation supernatant of the selected isolate was processed intoa freeze-dried powder. When used at a concentration greater than 6.250 mg/mL, the unpurified antimicrobial peptides hada strong bacteriostatic effect. The strain was identified as Lactobacillus casei by 16S rDNA gene sequencing. Raw wholemilk was fermented by inoculating this strain at 2, 3 or 4 g/100 mL, and stored at 4 ℃ for 30 days. The pH and syneresis offermented milk decreased with increasing inoculum size, whereas the titratable acidity, hardness, viscosity and water-holdingcapacity increased. The fermented milks with inoculum amounts of 3 and 4 g/100 mL did not significantly differ in sensoryevaluation scores, both higher than that inoculated at 2 g/100 mL.